Electrical windings



Sept. zo, 196e R. A. BEDARD 3,274,414

ELECTRICAL WINDINGS Filed oct. 4, 1963 2 sheets-sheet 1 Sept. 20, 1966R, A, BIDARD 3,274,414

ELECTRICAL WINDINGS Filed OCL. 4, 1963 2 Sheets-Sheet 2 INVENTOIL RENEHLP/ 50 loflfd) HffonLNE/S United States Patent O 1 s claims. (Cl.31o-26s) In some electric machines hav-ing flat rotors and/or stators,that is to say in which the windings are formed of bare lamellarconductors disposed flat on both sides of a thin and flat support madeof insulating material, this being achieved as a result of the so-calledprinted circuit technique or by any other means, and in which thecurrents are relatively high, it may happen that the conductors becometoo wide in the radial (or almost radial) portion, thus occasioninglosses by excessive eddy currents, whether the current be directed oralternating.

It is therefore necessary to split each basic conductor into ltwo ormore partial conductors in parallel and to choose the positions of thesepartial conductors suitably so as to avoid circulation currents betweenthem.

Here, however, a diiiiculty arises owing to the fact that the saidconductors are placed flat on the insulating support, covering the twofaces thereof practically completely, and that, moreover, not beinginsulated, they can form only a single layer on each face of the sa-idsupport.

The present invention has for its object to remedy this diiculty.

The invention is described hereinafter with the aid of various diagramsand figures given by way of nonlimitative example, the said supportbeing assumed to be a disc.

FIG. l is a fragmentary perspective view of a conventional flat windingformed of lamellar conductors.

FIG. la is a fragmentary section taken across the insulating support andshowing a few conductors on each side.

FIG. 2 is a diagrammatic plan View of an embodiment of the presentinvention.

FIG. 2a is a fragmentary section ysimilar to that of FIG. la, butapplicable to the embodiment of FIG. 2.

FIGS. 3-7 illustrate, in schematic fragmentary plan views, variousalternative embodiments.

The conventional flat winding illustrated 4in FIGS. 1 and la comprisesan insulating support 4, for example in the shape of a disc, bearing onits two faces bare lamellar conductors 1; outgoing ones A and returnones B on opposite sides, interconnected by means of connections 5extending through the thickness of the disc 4.

The present invention, as illustrated in FIGS. 2 and 2a, consists individing each initial basic conductor 1 into two partial conductors 2and 3, the Width of which is half that of the initial conductor, and indisposing one of these on one face of the thin insulating support 4 andthe other on the other face right opposite the previously mentionedpartial conductor, while taking advantage of the space left free in thisway between the partial conductors on one face, which have 'become halfas wide, and to do the same with those on the other face.

Connections 5 extend through the support 4 at the ends of the partialconductors 2 and 3 and connect them in parallel. Since -these conductorsare exactly back to back they encompass no magnetic flux and therefore,no circulation current between them is to be feared.

Holes are to be provided in the support for the connections 5. They mayall be located on two concentric circles or disposed in staggeredarrangement about such circles as shown in FIG. 2.

Only a few conductors have been shown, but in reality 3,274,414 PatentedSept. 20, 1966 the two faces of the support 4 are entirely covered withconductors; the partial conductors 3 are exactly opposite the partialconductors 2.

If a further subdivision of the conductors is required the inventionprovides that the initial conductor 1 be replaced by partial conductorsplaced this time side by side and that there be formed in this way halfloops which are joined by electrical connections so as to avoidcirculation currents. Various arrangements are possible, the diagrams ofthe principle of which are shown in FIG- URES 3 to 7 inclusive. In thesegures, there is shown each time an outgoing conductor A, in linear formfor simplicity.

In FIGURE 3, the initial conductor 1 is divided therein into fourpartial conductors 6, 7, 8, 9 forming two half loops which are toencompass the same linx, thus determining a suitable relation betweenthe division radius Rd, the permutation radius Rp and the reconnectionradius Rr.

It may happen that if the initial conductor has a width which is stillacceptable in the inner region of the beginning of the straight orradical portions, the subdivision need only be started at a radius Rdgreater than the commencing radius R1 of the straight portions, in whichcase the arrangement will be that shown in FIGURE 4.

More generally still, it is possible to subdivide the conductor firstinto two, then into four, then into eight, etc. partial conductors, asthe radius increases. There will then be obtained an arrangement with aprinciple similar to that of FIGURE 5, which is drawn for the case of adouble subdivision.

In the latter case, it will be necessary, in order to comply with thecondition of equality of iiuxes encompassed by all the closed circuitsobtained by following the conductors connected in parallel, that arelation similar to the foregoing one be observed between the divisionrad-ii Rdl and Rdz, the permutation radii R111, Rpz and the reconnectionradii Rrl and Rrz of each stage of subdivision.

It may then happen that the spacing of the various radii in an ordersuch as that shown in FIGURE 5. In this case, lin order to have regardboth for the correct radii Rd for the subdivisions and the condition ofux which iixes the permutation position, that is to say the radii Rp,

it may be necessary to permute the conductors in pairs in accordancewith the basic principle diagram of FIG- URE 6.

In most instances, however, this complicated arrangement may be avoided,while paying regard to the condition of flux, by modifying thesubdivision radi-i Rd (that is to say by making these subdivisions alittle sooner or a little later).

Finally, whatever the number of subdivisions, it may be advantageous, insome case, to effect in the outer curved portions of windingsreconnections of the partial conductors. A case of this kind is shown byway of example in the diagram of FIGURE 7, in which only the outerportion of the windings is illustrated.

Various solutions are possible for the material realisation of a simplesubdivision accompanied by permutation, that is to say for a singlestage of subdivision of the partial conductors in accordance with one orother of the basic principle diagrams described above, but it is clearlyunderstood that these solutions are applicable to every subassociatedportions of reduced width, half of said portions of each conductorextending over the opposite faces of said support, means extending fromone face of said insulating support to the other face thereof forconnecting said conductors to each other vat the ends thereof, and meansextending through said insulating support for electricallyinterconnecting said associated portions of each respective conductor tominimize eddy current losses in operation.

2. The winding assembly as claimed in claim 1, wherein the associatedportions of each respective conductor are positioned substantially backto back and are interconnected therethrough in parallel.

3. The winding assembly as claimed incla-im 1, wherein lthe associatedportions of each respective conductor comprise pairs of segmentspositioned side by side on a same face of saidsupport, said pairs beingconnected in series in a cross-like manner.

4. The winding assembly as claimed in claim 3, Wherein each respectiveconductor comprises a pair of segments on one face of the insulatingsupport and a pair of segments on the other face thereof, said pairs ofsegments being connected in a cross-like manner.

5. The winding assembly as claimed in claim 3, wherein each respectiveconductor comprises two pairs of segments on a same face of theinsulating support a conductor section of small length on the other facethereof, and two connections therethrough to interconnect in a crosslikemanner said segments through said conductor section.

References Cited by the Examiner UNITED STATES PATENTS 3,109,114 10/1963Henry-Baudet a B10-168 3,159,760 12/1964 Olofsson B10-268 X I MILTON O.HIRSHFIELD, Primary Examiner.

J. J. SWARTZ, Assistant Examiner.

1. AN ELECTRICAL WINDING ASSEMBLY COMPRISING A THIN SUPPORT OFINSULATING MATERIAL HAVING TWO SUBSTANTIALLY PLANAR PARALLEL FACES, AMULTIPLICITY OF BARE LAMELLAR ELECTRIC CONDUCTORS EXTENDING FLAT ON SAIDFACES, AT LEAST A LENGTHWISE PORTION OF EACH CONDUCTOR BEING DIVIDEDINTO ASSOCIATED PORTIONS OF REDUCED WIDTH, HALF OF SAID PORTIONS OF EACHCONDUCTOR EXTENDING OVER THE OPPOSITE FACES OF SAID SUPPORT, MEANSEXTENDING FROM ONE FACE OF SAID INSULATING SUPPORT TO THE OTHER FACETHEREOF FOR CONNECTING SAID CONDUCTORS TO EACH OTHER AT THE ENDSTHEREOF, AND